You know when you want to cut a hole in styrene, card or whatever,
and it's too small for the circle cutter and too big for a bit in the mini-drill,
or you want a nice circular disc with the same limitations.
Well health and safety merchants look away now,
but my favourite is simply a brass tube of suitable diameter with the inside edge of one end filed to a sharpish edge.
With an old T-shirt to stop the other end making a hole in your palm,
you can just press down and twist a few times and there's your hole or disc which will pop out of the end of the tube.
The deluxe version has a wooden block as a palm protector!
The tube does get shorter of course as lengths are removed from the non sharpened end for making boilers or what have you,
but then so does a pencil as it's sharpened!
I have seen some of those "tools"in a Micro-Mark catalog for mucho mas dinero.
(I ain't putting down MM, it just pays YOU to keep your eyes open)
Now, I'm back to drilling holes with a #11 Exacto blade.
____________________ It doesn't matter if you win or lose, its' how you rig the game.